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Controversy exists as to the potential of asphalt fumes to induce health effects including respiratory, hepatotoxic, nephrotoxic, or hematotoxic responses. The main purpose of this study was to ascertain whether occupational exposure to asphalt fumes, under normal working conditions, is associated with any respiratory, hepatotoxic, nephrotoxic, or hematotoxic response.In this cross-sectional study in which 210 subjects (80 exposed and 130 reference subjects) were investigated. Using standard methods, atmospheric concentrations of total particulate and benzene-soluble fractions of asphalt fumes, as well as total particulate were measured. Additionally, urine and blood samples were taken from subjects for complete blood count, white blood cell differential test, urinalysis, and routine biochemical tests of kidney and liver function. For The prevalence of respiratory symptoms among subjects was investigated by a standard questionnaire. Additionally, the parameters of pulmonary function were measured both, prior to exposure and at the end of work-shift.Both groups were similar as far as their demographic variables and smoking habits were concerned. The association between exposure to asphalt fumes and changes in most liver and kidney function tests and complete blood count parameters was statistically significant. Mean values of FEV1, both prior to the exposure (89.58% [SD 18.69%] predicted value) and at the end of shift (85.38% [SD 19.4%]), were significantly (p<0.05) smaller than those of the comparison subjects (93.88% [SD 13.93%]). Similarly, pre-shift (87.05 [SD 8.57]) and postexposure (89.95 [SD 6.85]) FEV1/FVC ratio were both significantly (p<0.01) lower than those of the unexposed employees (107.56 [SD 9.64]). The pattern of changes in parameters of lung function in asphalt workers was consistent with that of chronic obstructive lung disease.This study showed that exposure to sub-threshold limit value levels of total particulate and benzene-soluble fractions is associated with early liver and kidney dysfunction as well as haematological disorders. Also, significant decrements in the parameters of pulmonary function as well as, a significant increase in the prevalence of respiratory symptoms in asphalt paving workers compared to their unexposed counterparts provided evidence in favour of a significant association between exposure to asphalt fumes and lung function impairments.